LED PWM
PWM dimming nubuhanga bwibanze bwa dimming ikoreshwa mubicuruzwa bitanga ingufu za LED. Mubizunguruka byerekana ibimenyetso bisa, umucyo wo kugenzura luminaire usohoka muburyo bwa digitale. Ubu buryo bwo gucana bufite ibyiza byinshi ugereranije na gakondo ya analog signal dimming. Birumvikana ko hari inenge zimwe mubice bimwe. Ni izihe nyungu n'ibibi?
Reka tubanze turebe ihame ryibanze rya pwm dimming. Mubyukuri, mubikorwa bifatika byibicuruzwa, birashobora kumvikana ko umuyoboro wa MOS uhuza umutwaro wa LED. Anode yumugozi ikoreshwa nisoko ihoraho. Ikimenyetso cya PWM noneho gikoreshwa kumuryango wa transistor ya MOS kugirango uhindure byihuse umurongo wa LED kugirango ucike.
Ibyiza bya pwm dimming:
Ubwa mbere, pwm dimming ni dimming neza.
Kugaragaza neza ni ikintu kidasanzwe cyerekana ibimenyetso bya digitale bisanzwe, kubera ko pwm dimming ikoresha ibimenyetso bya pulse waveform hamwe nibisobanuro bihanitse.
Icyakabiri, pwm dimming, nta tandukaniro ryibara.
Muburyo bwose bwo kugabanuka, kubera ko urumuri rwa LED rwaba rufite agaciro ntarengwa cyangwa ruzimye, impuzandengo ya LED ihindurwa muguhindura igipimo cyimisoro, bityo gahunda irashobora kwirinda itandukaniro ryamabara mugihe cyimpinduka zubu.
Icya gatatu, pwm dimming, irashobora guhinduka.
Umuyoboro wa PWM muri rusange ni 200 Hz (dimimoni nkeya) kugeza kuri 20 kHz cyangwa irenga (dimingi yo hejuru).
Icya kane, pwm dimming, nta strobe.
Igihe cyose PWM dimming frequency iri hejuru ya Hz 100, nta guhindagurika kwa LED kugaragara. Ntabwo ihindura imikorere yimikorere yama soko ihoraho (kuzamura igipimo cyangwa kugabanuka kumanuka), kandi ntibishoboka gushyuha. Ariko, PWM pulse ubugari dimming nayo ifite ibibazo byo kumenya. Iya mbere ni uguhitamo impanuka ya pulse: kubera ko LED iri muburyo bwihuse, niba imikorere ikora ari mike cyane, ijisho ryumuntu rizumva rihindagurika. Kugirango ukoreshe byuzuye ibintu bisigaye bigaragara mumaso yumuntu, inshuro zayo zigomba kuba hejuru ya Hz 100, byaba byiza 200 Hz.
Ni izihe ngaruka mbi za pwm dimming?
Urusaku ruterwa no gucura ni rumwe. Nubwo idashobora kugaragara nijisho ryumuntu hejuru ya Hz 200, ni intera yo kumva abantu kugeza kuri 20 kHz. Muri iki gihe, birashoboka kumva amajwi yubudodo. Hariho inzira ebyiri zo gukemura iki kibazo. Imwe ni ukongera inshuro yo guhinduranya hejuru ya 20 kHz hanyuma ugasimbuka ugutwi kwabantu. Nyamara, hejuru cyane inshuro nyinshi zishobora gutera ibibazo bimwe na bimwe, kubera ko ingaruka ziterwa na parasitike zitandukanye zizatera impiswi ya pulse (imbere ninyuma) kugoreka. Ibi bigabanya ukuri kwijimye. Ubundi buryo ni ukumenya igikoresho cyumvikana kandi ukagikora. Mubyukuri, igikoresho nyamukuru cyumvikana ni capacitori ya ceramic isohoka, kubera ko ubushobozi bwa ceramic busanzwe bukozwe mumashanyarazi maremare ya dielectric ya ceramics, afite imiterere ya piezoelectric. Kunyeganyega kwa mashini bibaho munsi ya 200 Hz pulse. Igisubizo nugukoresha ubushobozi bwa tantalum aho. Nyamara, ubushobozi bwa tantalum nini cyane biragoye kubibona, kandi igiciro gihenze cyane, bizamura ibiciro bimwe.
Kurangiza, ibyiza bya pwm dimming ni: gukoresha byoroshye, gukora neza, gukora neza, hamwe ningaruka nziza. Ikibi ni uko kuva umushoferi rusange wa LED ashingiye ku ihame ryo guhinduranya amashanyarazi, niba PWM dimming frequency iri hagati ya 200 na 20 kHz, inductance hamwe nubushobozi bwo gusohora hafi ya LED dimming power itanga urusaku rwumvikana. ugutwi kwa muntu. Mubyongeyeho, mugihe ukora PWM dimming, uko wegereye inshuro yikimenyetso cyo guhinduranya ni inshuro ya chip ya shoferi ya LED ku kimenyetso cyo kugenzura amarembo, ingaruka mbi ni mbi.